<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>判断奇偶性</title>
    <script>
        var num = prompt(`请输入一个数:`);
        alert(`这是一个${num % 2 ==0 ? '偶数':'奇数'}`);
    </script>
</head>
<body>

</body>
</html>